Hazards of Industrial Gases
There are certain properties, hazards and precautions associated with the major industrial gases, as
well as mixtures of same. These gases are: Acetylene, Air, Argon, Carbon Dioxide, Helium, Nitrogen,
Nitrous Oxide, Oxygen, and Propane. Each of these gases has at least one of the following hazards:

High Pressure

Extreme cold

Asphyxiating (Inert)

Oxidizing

Flammable
NOTE: It should be stressed that more than one hazard can be associated with a particular gas.
Hazard: High Pressure

Most cylinder gases are under high pressure. Although most high pressure cylinders are filled to
pressures between 2000 psi and 3000 psi, cylinders with pressure ratings up to 7500 psi are
commonly available. Even lower pressure gases, such as Propane can be hazardous if the proper
equipment is not utilized, or if leaks are encountered.

Hazard: Extreme Cold
Some users of Argon, Carbon Dioxide, Helium, Hydrogen, Nitrogen, or Oxygen receive these
gases in cryogenic liquid form. Both the liquid and its vapor are extremely cold, ranging in
temperature from -109F to -452F.
The major hazards associated with these liquids are 1) danger of tissue destruction or severe
frostbite 2) danger of asphyxiation and/or increased risk of fire hazard 3) build up of extremely high
pressure from trapped evaporating liquids and 4) the embrittlement of many materials which may
fracture at these temperatures.
Hazard 3: Asphyxiating (Inert)
Argon, Carbon Dioxide, Helium and Nitrogen are all inert gases. They will not support life and may
cause asphyxiation by displacing the Oxygen in the air. To insure safety, the following precautions
should always be observed:
Areas where any inert gas is used or stored must be kept well ventilated. None of the inert gases
can be adequately detected by any human sense; yet all can be inhaled as readily as air. If the
Oxygen content drops below 19.5%, the reactions of personnel exposed will depend upon the
response of the individual involved. However, one should not expect to experience a choking
sensation, rather, there may be an almost immediate loss of consciousness.
Before entering confined spaces which can be Oxygen deficient atmospheres, you should first
check the Oxygen levels with an Oxygen analyzer. If there is the possibility of excessive Carbon
Dioxide in a confined space, it is not sufficient to merely check the Oxygen concentration. Carbon
Dioxide concentrations already in the blood stream, regulate certain bodily functions and excess
concentrations may act as a depressant on the central nervous system.
Hazard 4: Oxidizing
Two industrial gases that are recognized as oxidizers are Oxygen and Nitrous Oxide. Materials
which normally do not burn in air may burn with explosive violence in an Oxygen enriched
atmosphere.
To insure safety, the following precautions must always be followed:

Always refer to Oxygen by its name. NEVER call it "air" and NEVER use it as a substitute for
compressed air.

Keep all organic materials, especially oil, grease, wood, cloth, or asphalt, away from contact with
Oxygen.

Never attempt to lubricate any equipment used in Oxygen service. Arrange for repairs through your
supplier.

When liquid Oxygen is spilled or vented, a white cloud of condensed moisture results. Standing in
or near this cloud will saturate clothing with Oxygen, making it extremely subject to rapid and
intense burning. Should this happen, personnel involved should move to a clear area and avoid
smoking, open flames, or other sources of ignition for at least one half hour to allow clothing to
adequately air out.

Prevent spillage onto asphalt or oil contaminated concrete, soil or other surfaces.

Hazard 5: Flammable
Acetylene, Hydrogen, and Propane are flammable gases. If any of these gases mix with air or
Oxygen, the mixture is subject to ignition or explosion if exposed to an ignition source. The
concentrations needed are low. 2.2% in air for Propane, 2.5% for Acetylene, and 4% for Hydrogen.
In order to avoid accidents, observe the following safety precautions:

Store cylinders containing flammable gases outdoors or in well ventilated areas. Away from
oxidizers and never near sources of heat, flames, or sparks.

Never use a flame to detect flammable gas leaks.

Never permit the delivery pressure of Acetylene to exceed 15 psig.

Never attempt to transfer Acetylene into another cylinder or mix any gas with Acetylene in a
cylinder.

Acetylene should not be exposed to copper, silver, mercury, their salts, compounds and alloys.
Explosive acetylide compounds may be formed.

Hydrogen gas burns with an almost invisible pale blue flame. If there is suspicion that Hydrogen is
burning, approach with a broom extended into the suspected flame region to confirm the presence
of burning. If the Hydrogen is burning, the broom will ignite. Call the fire department as soon as a
fire is detected, unless the fire can be easily quenched by shutting off the source of the gas and the
fire has not spread to adjacent areas or articles.

Propane is much heavier than air, therefore, it will flow to low points, to be ignited at distances that
may be quite far